Hull Pincelli
Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA.
Curr Biol. 2015 Oct 5;25(19):R941-52. doi: 10.1016/j.cub.2015.08.053.
The vast majority of species that have ever lived went extinct sometime other than during one of the great mass extinction events. In spite of this, mass extinctions are thought to have outsized effects on the evolutionary history of life. While part of this effect is certainly due to the extinction itself, I here consider how the aftermaths of mass extinctions might contribute to the evolutionary importance of such events. Following the mass loss of taxa from the fossil record are prolonged intervals of ecological upheaval that create a selective regime unique to those times. The pacing and duration of ecosystem change during extinction aftermaths suggests strong ties between the biosphere and geosphere, and a previously undescribed macroevolutionary driver - earth system succession. Earth system succession occurs when global environmental or biotic change, as occurs across extinction boundaries, pushes the biosphere and geosphere out of equilibrium. As species and ecosystems re-evolve in the aftermath, they change global biogeochemical cycles - and in turn, species and ecosystems - over timescales typical of the geosphere, often many thousands to millions of years. Earth system succession provides a general explanation for the pattern and timing of ecological and evolutionary change in the fossil record. Importantly, it also suggests that a speed limit might exist for the pace of global biotic change after massive disturbance - a limit set by geosphere-biosphere interactions. For mass extinctions, earth system succession may drive the ever-changing ecological stage on which species evolve, restructuring ecosystems and setting long-term evolutionary trajectories as they do.
绝大多数曾经存在过的物种都在某次大灭绝事件之外的某个时间灭绝了。尽管如此，大规模灭绝被认为对生命的进化史产生了巨大影响。虽然这种影响部分肯定是由于灭绝本身造成的，但我在此探讨大规模灭绝的后续影响可能如何促成这些事件在进化方面的重要性。在化石记录中出现大量分类群消失之后，紧接着是长时间的生态动荡期，这创造了那个时代特有的选择机制。灭绝后续阶段生态系统变化的节奏和持续时间表明了生物圈与地球圈之间的紧密联系，以及一个此前未被描述的宏观进化驱动因素——地球系统演替。当全球环境或生物变化（就像跨越灭绝边界时发生的那样）将生物圈和地球圈推离平衡状态时，地球系统演替就会发生。随着物种和生态系统在后续阶段重新进化，它们会在地球圈典型的时间尺度上（通常是数千到数百万年）改变全球生物地球化学循环——进而又改变物种和生态系统。地球系统演替为化石记录中生态和进化变化的模式及时间提供了一个一般性解释。重要的是，它还表明，在大规模干扰之后，全球生物变化的速度可能存在一个限制——这个限制是由地球圈与生物圈的相互作用所设定的。对于大规模灭绝而言，地球系统演替可能推动了物种进化的不断变化的生态舞台，在其进行过程中重塑生态系统并设定长期的进化轨迹。
